Conventionally, as this type of a paint drying oven, a drying oven is known in which air heated by a burner is circularly supplied into a drying chamber into which a workpiece is to be supplied (for example, see Patent Literature 1). Further, in recent years, there has been proposed a configuration that includes a flame holding cylinder surrounding a flame of a burner and a burning cylinder covering the flame holding cylinder from outside, where low temperature air is supplied into the burning cylinder from outside.